Explain why chlorine (Cl²) is a gas at room temperature, but at sodium chloride (NaCL) is a solid at room temperature.
Therefore chlorine has a low boiling point and so is a gas at room temperature. In contrast, sodium chloride is a solid at room temperature as it is a giant ionic compound. The individual sodium and chloride ions are held together by electrostatic forces of attraction between the oppositely charged ions
Chlorine (Cl₂) and sodium chloride (NaCl) have different chemical properties that contribute to their states at room temperature. The state of a substance, whether it is a gas, liquid, or solid, is determined by the balance of forces between the particles that make up the substance.
Chlorine gas (Cl₂) exists as a diatomic molecule, which means two chlorine atoms are bonded together. At room temperature, chlorine gas is a greenish-yellow gas. The reason chlorine is a gas at room temperature is due to its relatively weak intermolecular forces and low boiling point. Chlorine atoms in the Cl₂ molecule are held together by a covalent bond, where they share electrons. The intermolecular forces between chlorine molecules are weak London dispersion forces, which are a result of temporary fluctuations in electron distribution. These forces are relatively easy to overcome, so chlorine molecules can easily separate from one another and exist in a gaseous state.
On the other hand, sodium chloride (NaCl) is an ionic compound composed of sodium (Na⁺) ions and chloride (Cl⁻) ions. At room temperature, sodium chloride is a white crystalline solid. The solid state of sodium chloride is due to the strong electrostatic forces of attraction between the positively charged sodium ions and negatively charged chloride ions. These forces, called ionic bonds, require a significant amount of energy to break. Because of these strong forces, the particles in sodium chloride are held in a rigid, three-dimensional lattice structure, resulting in a solid state at room temperature.
To summarize, chlorine (Cl₂) is a gas at room temperature because its weak intermolecular forces and low boiling point allow the chlorine molecules to easily separate from one another. Sodium chloride (NaCl), on the other hand, is a solid at room temperature due to the strong ionic bonds between the sodium and chloride ions, which require a significant amount of energy to break.